Planing surface for aircraft and hydrocraft



g- 1953 o. B. DOOLITTLE EI'AL 2,647,709

PLANING SURFACE FOR AIRCRAFT AND" HYDROCRAF'T Filed Feb; 6. 1950 INVENTORS Donald BJJOOIH'I'IQ Jack R. Walden.

ATTORNEY Patented Aug. 4, 1953 PLANIN G SURFACE FOR AIRCRAFT AND HY DROCRAFT Donald B. Doolittle and mington, Del., assignors, to All American Engin Jack R. Walden, Wilby mesne assignments,

eering Company, Wilmington, Del., a corporation of Delaware Application February 6, 1950, Serial No. 142,654

6 Claims.

Our present invention relates to aircraft undercarriages equipped for safe landings on various surface mediums, as Water, snow, mud, grass or any combination of these mediums.

I-Ieretofore, there have been developed various pontoon arrangements for landing on water. These pontoons are bulky and displace considerable water making all landings and take-ofis slow. Also, pontoon structures cannot land safely on other than water surfaces, unless they are incorporated with landing wheels. The many disadvantages of pontoons are avoided by our present discovery and invention of a novel hydroski for airplanes. This hydro-ski permits safe, efiicient and extremely rapid landings and takeoffs from water of any depth, and in addition permits substantially equal landing and takeoff performances on landing surfaces of all descriptions, such as marshes, grass, and the like.

An object of our invention is to provide a novel planing surface for airplane undercarriages adapted to land on many forms of landing medium.

Another object of our invention is to provide a hydro-ski for airplanes.

A more specific object is to provide a ski for airplanes which permits landing on water or land surfaces and also permits taking-off from water or land surfaces.

Another object is to provide a novel hydro-ski formed with a variable planing surface adaptable for landings and take-offs on and from any suitable medium.

A further object is to provide automatic control of the variable planing surface of a landing ski.

Many other objects and advantages of our invention will appear from the following detailed description, which refers by reference, numerals to the several similarly numbered parts of the attached drawing embodying one form of the invention.

In the drawing:

Figure 1 is a top side perspective view of one form of our hydro-ski with a variable planing area.

Figure 2 is a top side perspective view of the form of Figure 1 shown with the planing area increased to maximum.

Figure 3 is a partial cross section view of one part of the connecting means used in the present form of our invention for varying the planing surface, taken along line 33 of Figure 2.

Figure 4 is a partial cross section view taken transversely of the variable planing surface actuator shaft and its connecting rods or links coupled to the part shown in Figure 3 and taken on the line 4-4 of Figure 5.

Figure 5 is a top view of the said actuator shaft partly in cross section and partly in elevation.

Referring in detail to the drawing and first with particular reference to Figure 2, there is illustrated a top view of a hydro-ski l0 formed with a central reinforcing rib II along its top section and a variable planing surface comprised of a main central section I2 with a planing surface I3 and side flap sections I4 and I5 having auxiliary planing surfaces I 6 and I7, respectively. Each auxiliary planing surface is pivotally secured along each longitudinal edge of the main planing surface I3 by suitable means, such as the elongated hinge I8.

The hinge I8 permits the auxiliary planing surfaces I6 and ll of the side ski flap sections to swing angularly with respect to the main planing surface I3 of central section I2 from an aligned unfolded position, as in Figure 2, into a folded position, as shown in Figure 1.

The central reinforcing rib II of the hydro-ski is formed with a Pyramidal axle mounting I9. The axle mounting I9 has a through transverse opening 20 for receiving the axle of the aircraft undercarriage, to thereby mount the ski for use. The axle mounting of each pair of hydro-skis used serves as an operating base for the thread end 2 I of an actuating rod 22.

The threaded end 2I of the actuating rod 22 threads completely through the axle mounting I9 in a threaded opening formed therein below and at right angles to the axle opening 20 and the unthreaded end of the rod is slidable through guide fittings 23 and 24 on top of the rib l I. The sliding action of the rod 22 caused by the threading in and out of the same in the axle mounting may be driven by any suitable power means, such as the gear train 26 and electrically or hydromatically driven shaft arrangement shown in Figures 1 and 2.

The actuating shaft 22 is formed with spaced apart short sections 25 of reduced diameter, thereby providing oppositely facing shoulders 21 and 28. Loosely encircling each reduced section 25 are pairs of connections 29 and 30 with apertured bifurcated ends 3| and 32. Each pair of connections have their respective bifurcated ends 3! and 32 extending radially from the rod 22 in opposite directions and pivotally connect with the apertured end of a link arm 33. When the bifurcated ends are coupled to a link arm 33 by suitable means, such as a vertical rivet or pin 34, see Figures 4 and 5, care is had to have the actuating rod 22 positioned on the rib I I so that each set of connections 29 and 30 are on the inner or leading side of the fittings 23 and 24, respectively. When thus positioned the fittings serve as limit stops to control the axial thrust of the actuating rod 22 when the flap sections I4 and I5 are unfolded as will be more fully explained hereinafter.

There are similar link arms 33 connected to each one of the bifurcated ends of the connections 29 and 30. As shown in Figure 2 these links extend from each side of the actuating rod 22, and each of their extended ends are pivotally coupled by a pin 34 to a swivel bushing 35 formed with upstanding spaced apart apertunedg ears 36. through which the pin 34 extends, see Figure 3. Each of the bushings 35 have a base formed with a central opening mounted on a bearing plate 31 also with an opening aligned with; the opening in the bushing base. Each swivel bushing 35 and the bearing plate 318566; secured Q? gether by a headed rivet 38; riveted; to the! top. surface of their respective foldable ski section"- or flap I l or [5, so the bushingis free to swivel or turn on bearing plate; 36!; when, the: actuating rod 22 is pulled forward with; the rms 33 to raise or fold the side sections or flaps l4 and 15,. As shown these side flaps are of tri: angular shape to thereby merge with the leading end. of' the ski body H];

p ration; The variable planing surfacesof the hydroskis are controlled from the pilot-sseatbyany; 1

suitable control means, not shown. This; controlmeans imparts powerthroughshaft 40* and gear train 26=to drive the actuating rod'-22*, see Figures 1 and 2.

When landing a plane equipped with hydroskis onwater the pilot maintains a; taxiingspeed as low or high as necessary to keep; afloat: Themore planing surface; area provided the slower the taxiing" speed ma beand accordinglyasthe aircraft is sloweddownthepilot may unfold-the flaps It and Ht to increase the planing surface and thuscompensate for reducing'taxiing speeds. When the flaps- I l and I5" are folded as in Figure l, the actuating rod 22' is positionedforwardfromthetrailing endot the rib I l-and'the, connecting links- 33; are angularly directed, toward theaxlemount; it: This position of; the links is permitted because of -the swivel bushing and the pivoted connection of; each link 33, on a pin 3d: Theforwardmovement' is stopped bysuitable; means; suchv as enlarged-nut" G1 on the end of shaft- 22-:

Aspoweris" applied togtheactuating rod 2 2' through gear train 28,; for example, the thread section- 21 moves axially toward". the trailing, end ofthe hydro-ski lii and turns the links 33 on their respective pivot 311:; untiltheconnections d tdand"31*32' abut againstthe actuator-shaft orred guides Z'Efilfld'ifii respectively. During the rearward sliding movementaof" the actuatorrod 2-2'the links'iiii impart'power to unfold the flapsorside-sectionsldand Hi" to the substantially aligned'position shown inFi'gure 2 for maximum area planing surface and minimum low taxi speeds.

Thus we haveprovided a novel undergcarriage arrangement including hydro-skis tor airplanes, which replace theusual landing wheels-or pontoons and have many advantages thereover; For example, craftequipped with hydro-skis" is superior to an aircraft; equipped with wheels due to the reduced drag of the ski'configuration. Also, when taking of? from water; acceleration from taxiing speedtotake-off is materially more rapid than with conventional floats andithereis-much lessspray and water disturbancewhen using hydro-skis Then" also hydTOfiSk'iS' permit landing on any' surface, which is? not possible; with conventional landing gear;

Without further description itis: believed'that the foregoingissufiicientlycomplete; clear; concise'and exact intermsto-- enable any'person: skilled in the art to-practice our invention: However; it is -tobeexpressly understood that al-' though i onlyone formof ourzinventionyisv de scribed and, illustrated inadetail that other parts, arrangements and combinations of parts, which may now occur to others are likewise intended to be covered hereby. To determine the scope of our invention reference should be had to the appended claims.

Wealaimz.

l. Landing gear for airplanes equipped with hydro-skis, having a water planing surface, the planing surface diverging rearwardly in width, andisaidiskishaving axle mountings for connection onthe axles of the said gear.

2. In connection with landing gear for airplanes having the usual axles and shock absorbing struts, a hydro-ski comprising aplaning surface rearwardly diverging in Width, a centrally positioned elongated longitudinal reinforcing rib, and-an axle mounting.

3; A hydro skifor airplanes comprising a variablearea planing surface, said surface being formed of a mainv central section and foldab'le side flap sections, a top reinforcing rib formed with said central section, an axle mounting formed intermediate: the rib, and pilot controlled operating means partly mounted in the said axle mounting and connecting with each side flap section for folding or unfolding said side sections.-

4. As an article of manufactureahydro-ski for airplanes comprising a main body with a forwardly and u wardly curved leading end and a fiat trailing end, elongatedside flaps pivoted to-eachlongitudinal'side edge of said body; a longitudinallyextending reciprocatable actuating rod connected to a pilot controlled source of power, connecting links pivoted at intermediate spaced positions on the said rod; each of said links beinguniversally connected to the top surface of the said side-flaps, to there'- by-permit' the side-flaps to be-fo'lded over the said-main body of the ski;

5." An undercarriage for-aircraft including a pair of variable area planing surfacemembers, each member-- comprising amain body formed with' an axle mounting, said body having an upwardly cmved' leading end and a relatively flat trailing end, elongated triangularflapspivotally secured to eachlongitudinal side" edgeof the main body, and remote control flapactuating means supported by the main body and connected to-each -flap for varying the'are'a' of the pl-aningsurfaces of' said members by pivotal movement of said flaps.

6. Landing gear for airplanes equipped with hydro slcis:or-thglike; each ski'liaving a vari able position planing surface, said planingsurface of each ski including pilot: controlled side planing sectionsyertically movable with' respect to-planingposition, and each ofi.said sl-:'is having axle mountings for connection on the axles ofzsaid respectiveilandinggear.

DONALD Bi DOOLITTLE; JACK RLWALDEN'.

References Cited: in the, file. of 1 this? patent UNITED STATES PATENTS Number, blamev Date 2,085,295 Campbell June 29', v1937 2,410,702 Arsenault Nov. 5,1946 2,448,075 Bortner Aug. 31, 1948 FOREIGN PATENTS-.

Number 7 Country Date-'- '77 1, 622 France- July 30, 1934 

